William Rea Furlong (May 26, 1881 – June 2, 1976) was United States Navy Rear admiral during World War II, who served as the Chief of Naval Ordnance from 1937 to 1941.

In 1910, Furlong was assigned to the protected cruiser USS Chicago, which was posted as the reserve of the Massachusetts Naval Militia.

He served on Chicago until 1912, when he attended the Columbia University, New York and graduated with the Master of Science degree in electrical and radio engineering in 1914.

From 1928 to 1931 he served as Chief of Policy and Liaison Section, Office of Island Government, Navy Department, Washington, D.C. From 1931 to 1933 he commanded the light cruiser USS Marblehead.

On June 23, 1938, he was promoted to rear admiral and assigned as Chief of the Bureau of Ordnance for the Navy Department in Washington, D.C. From February to December 1941, he served as commander of Minecraft, Battle Force at Pearl Harbor, Hawaii.

He was present at the attack on Pearl Harbor on 7 December 1941, when he was on board his flagship, the minelayer USS Oglala, when it capsized after being strafed and torpedoed by the Japanese.

It has been posited by Slate writer Alec Nevala-Lee that Furlong is the most convincing candidate for the creator of the 50-star flag of the United States.

In 1981 Furlong's book So Proudly We Hail: The History of the United States Flag was published by the Smithsonian Institution Press.